sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Co-developed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Joel Granados <j.granados@samsung.com>

include/linux/ftrace.h

@@ -471,7 +471,7 @@ static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
 
 extern int stack_tracer_enabled;
 
-int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
+int stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer,
 		       size_t *lenp, loff_t *ppos);
 
 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
@@ -1175,7 +1175,7 @@ extern int tracepoint_printk;
 extern void disable_trace_on_warning(void);
 extern int __disable_trace_on_warning;
 
-int tracepoint_printk_sysctl(struct ctl_table *table, int write,
+int tracepoint_printk_sysctl(const struct ctl_table *table, int write,
 			     void *buffer, size_t *lenp, loff_t *ppos);
 
 #else /* CONFIG_TRACING */

include/linux/mm.h

@@ -204,11 +204,11 @@ extern int sysctl_overcommit_memory;
 extern int sysctl_overcommit_ratio;
 extern unsigned long sysctl_overcommit_kbytes;
 
-int overcommit_ratio_handler(struct ctl_table *, int, void *, size_t *,
+int overcommit_ratio_handler(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
-int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
+int overcommit_kbytes_handler(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
-int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
+int overcommit_policy_handler(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
 
 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
@@ -3854,7 +3854,7 @@ extern bool process_shares_mm(struct task_struct *p, struct mm_struct *mm);
 
 #ifdef CONFIG_SYSCTL
 extern int sysctl_drop_caches;
-int drop_caches_sysctl_handler(struct ctl_table *, int, void *, size_t *,
+int drop_caches_sysctl_handler(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
 #endif
 

include/linux/perf_event.h

@@ -1582,11 +1582,11 @@ extern int sysctl_perf_cpu_time_max_percent;
 
 extern void perf_sample_event_took(u64 sample_len_ns);
 
-int perf_event_max_sample_rate_handler(struct ctl_table *table, int write,
+int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos);
-int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
+int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos);
-int perf_event_max_stack_handler(struct ctl_table *table, int write,
+int perf_event_max_stack_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos);
 
 /* Access to perf_event_open(2) syscall. */

include/linux/security.h

@@ -228,7 +228,7 @@ struct request_sock;
 #define LSM_UNSAFE_NO_NEW_PRIVS	4
 
 #ifdef CONFIG_MMU
-extern int mmap_min_addr_handler(struct ctl_table *table, int write,
+extern int mmap_min_addr_handler(const struct ctl_table *table, int write,
 				 void *buffer, size_t *lenp, loff_t *ppos);
 #endif
 

include/linux/sysctl.h

@@ -61,31 +61,31 @@ extern const int sysctl_vals[];
 
 extern const unsigned long sysctl_long_vals[];
 
-typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
+typedef int proc_handler(const struct ctl_table *ctl, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
 
-int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_dobool(struct ctl_table *table, int write, void *buffer,
+int proc_dostring(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dobool(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
-int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
+int proc_dointvec(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_douintvec(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec_minmax(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_douintvec_minmax(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
-int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
+int proc_dou8vec_minmax(const struct ctl_table *table, int write, void *buffer,
 			size_t *lenp, loff_t *ppos);
-int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+int proc_dointvec_jiffies(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dointvec_ms_jiffies_minmax(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos);
-int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
+int proc_dointvec_userhz_jiffies(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
-int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
+int proc_dointvec_ms_jiffies(const struct ctl_table *, int, void *, size_t *,
 		loff_t *);
-int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
+int proc_doulongvec_minmax(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_doulongvec_ms_jiffies_minmax(const struct ctl_table *table, int, void *,
 		size_t *, loff_t *);
-int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
+int proc_do_large_bitmap(const struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_do_static_key(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
 
 /*
@@ -287,7 +287,7 @@ static inline bool sysctl_is_alias(char *param)
 }
 #endif /* CONFIG_SYSCTL */
 
-int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
+int sysctl_max_threads(const struct ctl_table *table, int write, void *buffer,
 		size_t *lenp, loff_t *ppos);
 
 #endif /* _LINUX_SYSCTL_H */

include/linux/vmstat.h

@@ -17,7 +17,7 @@ extern int sysctl_stat_interval;
 #define DISABLE_NUMA_STAT   0
 extern int sysctl_vm_numa_stat;
 DECLARE_STATIC_KEY_TRUE(vm_numa_stat_key);
-int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
+int sysctl_vm_numa_stat_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *length, loff_t *ppos);
 #endif
 
@@ -301,7 +301,7 @@ void cpu_vm_stats_fold(int cpu);
 void refresh_zone_stat_thresholds(void);
 
 struct ctl_table;
-int vmstat_refresh(struct ctl_table *, int write, void *buffer, size_t *lenp,
+int vmstat_refresh(const struct ctl_table *, int write, void *buffer, size_t *lenp,
 		loff_t *ppos);
 
 void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *);

include/linux/writeback.h

@@ -350,7 +350,7 @@ extern unsigned int dirty_expire_interval;
 extern unsigned int dirtytime_expire_interval;
 extern int laptop_mode;
 
-int dirtytime_interval_handler(struct ctl_table *table, int write,
+int dirtytime_interval_handler(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos);
 
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);

include/net/ndisc.h

@@ -486,7 +486,7 @@ void igmp6_event_report(struct sk_buff *skb);
 
 
 #ifdef CONFIG_SYSCTL
-int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write,
+int ndisc_ifinfo_sysctl_change(const struct ctl_table *ctl, int write,
 			       void *buffer, size_t *lenp, loff_t *ppos);
 #endif
 

include/net/neighbour.h

@@ -412,12 +412,12 @@ void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
 void neigh_seq_stop(struct seq_file *, void *);
 
-int neigh_proc_dointvec(struct ctl_table *ctl, int write,
+int neigh_proc_dointvec(const struct ctl_table *ctl, int write,
 			void *buffer, size_t *lenp, loff_t *ppos);
-int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
+int neigh_proc_dointvec_jiffies(const struct ctl_table *ctl, int write,
 				void *buffer,
 				size_t *lenp, loff_t *ppos);
-int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
+int neigh_proc_dointvec_ms_jiffies(const struct ctl_table *ctl, int write,
 				   void *buffer, size_t *lenp, loff_t *ppos);
 
 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,

include/net/netfilter/nf_hooks_lwtunnel.h

@@ -2,6 +2,6 @@
 #include <linux/types.h>
 
 #ifdef CONFIG_SYSCTL
-int nf_hooks_lwtunnel_sysctl_handler(struct ctl_table *table, int write,
+int nf_hooks_lwtunnel_sysctl_handler(const struct ctl_table *table, int write,
 				     void *buffer, size_t *lenp, loff_t *ppos);
 #endif